Organo tin compounds and compositions containing same



Patented Aug. 11, 1953 ORGAN 0 TIN COMPOUNDS AND COMPOSI- TIONS CONTAINING SAME Elliott L. Weinberg, Long Island City, N. Y., and Ernest Vt. Johnson, VVestfield, 'N. J., assignors to Metal & Thermit Corporation, New York, N. Y., a corporation of New Jersey No Drawing. Application June 21, 1951, Serial No. 232,878

23 Claims.

The present invention relates to novel organotin derivatives of mercapto compounds, to processes for manufacturing the same, and to resin compositions containing these compounds as a stabilizer.

In accordance with the present invention, the new group of compounds may be generally designated as condensation products of certain organo-tin compounds with mercapto acids and esters. More particularly these compounds may be illustrated by the following structural formulas:

RsSnSR/COOR' R2Sn(SR'COOR")2 and RSn(SR/COOR 3 particularly vinyl halide resins, to any known \i stabilizer in quantities as low as one half of one percent of the weight of the resin. This superior stabilizing property is equally applicable to resinplasticizer compositions, inclusive of the phosphate type plasticizers, the use of which has heretofore been prohibitive due to their instability even in the presence of known stabilizers. However, the mercapto acid ester derivatives and the like of organo-tin compounds impartstabilization to the phosphate plasticizer resin systems, permitting thereby the production of superior fireproof plastic compositions.

These compounds may be prepared in any suitable manner. It has been found however that these novel products may be prepared in high yield and purity by reacting an organo-tin compound with mercapto-acids and mercaptoacid esters, and recovering a reaction product having the desired Sn-S linkage and ratio. More specifically, an organo-tin compound selected from the group consisting of organo-tin hydroxide, oxide, and stannoic acid may be condensed with an appropriate amount of a mercapto acid or mercapto acid ester' to produce products having the above structural formulas. An organo-tin halide having the formula RSIlXs, RzSnXz, or RsSnX wherein X is a halide, such as chlorine, may also be employed as the reactant with the mercapto acids or esters. However, for optimum results, it is preferable to conduct these reactions in the presence of basic substances or alkaline neutralizing agents (hydrogen ion acceptors) such as oxides, hydroxides (e. g. sodium hydroxide) carbonates (e. g. sodium and potassium carbonate), and tertiary amines (e. g. pyridine), etc. These substances accept the hydrogen ion formed during the condensation reaction and are not deleterious to the mercapto acid or ester when used in the prescribed manner. Basic substances of the character of ammonia, primary and secondary amines, should not be employed ordinarily, because they tend to react with esters, and thereby decrease the yield of desired ester products.

The reaction mechanism for the formation of the bis-mercapto derivatives using organo-tin oxide is clearly illustrated by the following equation:

This equation graphically shows that the reaction occurs between the mercapto radical and the organo-tin oxide, whereby water splits off and a chemical bond is formed between the tin and the sulfur. It further illustrates the necessity of two molecules of the mercapto compound per mole of tin containing reactant in order to obtain the desired reaction and the desired end produce having a 2:1 ratio of sulfur to tin.

Similarly, products of the formula require a 3:1 ratio of sulfur to tin. Using stannoic acid as a reactant, the reaction may be illustrated as follows:

RSnOOH+3 (HSRCOOR' 3 Products of the formula RsSnSR'COO require a 1:1 sulfur to tin ratio. Thus using organotin chloride as a reactant, the reaction may be graphically represented as follows:

RaSnCl-i-HSR'COOR RsSnSR/COO '+HC1 It is within the scope of this invention that pure, impure or commercial grades of the reactants may be employed satisfactorily. In general, pure compounds of the above formulas may be prepared from pure raw materials. Howeven.

these novel compounds may be diluted with. in-

nocuous, inert materials, thereby permitting the reaction has started. Thus, for example, the

initial reaction temperature may be within the broad range of 19 C.28 C. and the final reaction temperature may be within the ranges of 24 C.4=0 C. However, the presence of the water produced by the condensation reaction usually requires an additional heating or refluxing in order to strip said water from the reaction product, though it may be removed in any suitable manner.

Another feature of this invention is the use of inert organic solvents as the medium for' the reaction, such as toluene, benzene, methyl alcohol, etc. The presence of such solvent'fa'eilitates the desired reaction. The solvent may be eliminated from the reaction product at the completion of the reaction by any suitable means This may be accomplished by vaporizing: the solvent under vacuum at elevated temperatures. Pressures of about 2 to 30 mm. and temperatures of 75-160 C. are satisfactory in effecting removal of toluene or like solvent, from the reaction product.

By the procedures of this invention, these novel organo-tin derivatives of mercapto-acids and mercapto-acid esters can be obtained in almost theoretical yields. These yields are'indicative of the non-necessity of the use of an excess of either reactant, the total amount of starting materials being substantially completely utilized in the formation of the final reaction product.

The following examples are further illustrative of these novel products and their preparation, and it will be understood that the invention. is not limited thereto.

Example I Mercaptoacetic acid, 97% (194 gms.) 3,5,5 trimethyl hexyl alcohol (288 gms.), paratoluenesulphonic acid (2 gins.) (esterification catalyst) and 100' ml. of toluene were placed in a glass water was extracted. The final pot temperature was 160 C. The toluene was then stripped in vacuo at 10 mm. pressure; the trimethyl hexyl mercaptoacetate was distilled at C. at 10 mm. Sulfur content as calculated was 14.68% and as actually found was 14.68%.

The trimethyl hexyl mercaptoacetate (333 gms.) was added to a stirred slurry of 189 gms. dibutyltin oxide in 350 cc. of toluene. An exothermic reaction in which the temperature rose from 28 C. to 38.5? C. ensued; The slurry became slightly turbid in contrast with the initial opaque appearance. The temperature was then raised to toluene reflux. Using a moisture trap, water (-1 1-.8-gms.)- was removed from the product. Toluene was removed by vacuum distillation. The dibutyltin 8,5 bis (3,5,5 trimethylhexyl' mercaptoacetate) was a slightly viscous colorless liquid. (98% yield). The calculated analysis would be Sn, 17.76% and 9.62%. Analysis showed Sn, 17.41% and S, 9.35%.

Example II Cyclohexanol gms.) mereaptoacetie acid (97%-4'46 gms.) amL 50 m1. of toluene were placed in a reaction flask, fitted with a Barrett moi'sturetrap and reflux condenser. The theoretical amount of water (32 cc.) was separated in 1 hours. The final pot temperature was C. The resulting cycl ohexyl mercaptoacetate distilled at 105-10 C. at 10 mm. pressure. Sulfur content calculated 18.40%; found 18.11%.

The cyclohexyl mercaptoacetate (179 gms.) was added to 126- gms. of dibutyltin oxide slurried in 240 cc. of toluene. An exothermic reaction ensued'-thetemperature rising from 363 to 40 C. and, at the same time, the mixture became clearer. The mixture was then heated to remove water of reaction via a Barrett moisture trap (8.8 cc. were separated). The final pot temperature was 119 C. The toluene was then stripped at 18 mm. pressure; the final pot temperature was 135 C. The dibutyltin S,.S' bis (cyclohexyl mercaptoacetate) was a slightly yellow liquid. which had the following analyses: Sn=19.91%; S=10.80%. A calculated composition calls for Sn=20.30%; s=10.93%.

Example III Phenoxyethanol (276.4 gms. Dowanol 1), mercaptoacetic acid 97% (200 gms.) and 100 ml. of toluene were refluxed and the theoretical amount of water was removed in 3' hours. The toluene and excess mercaptoacetic acidwere stripped by heating to 100 C. at 10 Sulfur content found 12.77%; calculated 15.10%.

The phenoxyethyl mercaptoacetate (167 gms.) was added to 83 gms. of dibutyltin oxide slurried in 260 cc. of toluene. Temperature rise from 23 to 28 C. was noted. 5.1 cc. of water were removed in one hour. After the solution was clarified by filtration, the toluene was stripped to a pot temperature of 125 C. at 9 mm. pressure. The dibutyltin S,S bis (phenoxyethyl mercaptoacetate) was a light colored liquid. It analyzed 14.10%. Sn and 9.51% S. Calculated Sn and S contents are 16.23% and 8.73% respectively. Due to the technical nature of Dowanol. 1, the ester and reaction product are contaminated with inert diluents.

Example IV were refluxed to remove 21 ml. of water. Ex-

cess acid. and toluene were removed by vacuum stripping. The n-octadecyl mercaptoacetate was a white, low-melting solid. It analyzed 9.20% S as compared with 9.29% S calculated.

The above ester (184 gms.) was melted and added to dibutyltin oxide (62.5 guns.) slurried in 210 cc. of toluene. Water of reaction was removed, the solution was clarified by filtration and toluene was stripped. The resulting compound was a colorless, low-melting solid. It analyzed 12.25% Sn and 6.61% S, as compared with 12.28% Sn and 6.61% S for the calculated content.

Example v Dihydroabietyl mercaptoacetate was prepared by refluxing a toluene solution of mole of Abitol (85% hydroabietyl alcohols, 186 gms.) with mole of mercaptoacetic acid (48 gms.). About 9 cc. of water were removed at the time the esterification was stopped. No catalyst was used.

To this toluene solution of the hydroabietyl mercaptoacetate was added dibutyltin oxide (62.5 gms. mole). The'exothermic reaction which resulted caused the temperature to rise from 22 C. to 28 C. An hour of refluxing removed the water of reaction (4.5 cc.). The solution was filtered and the toluene was stripped in vacuo. The dibutyltin S, S bis (dihydroabietyl mercaptoacetate) analyzed 11.05% Sn, 5.68% S.

Example VI Trimethyl nonyl mercaptoacetate was prepared by placing 1 mole, 95 gms., of 97% mercaptoacetic acid and 1 mole, 186 gms., of commercial trimethyl nonyl alcohol with 100 ml. of toluene and boiling chips in a reaction flask. No esterification catalyst was used. The theoretical amount of water was over in about 14 hours. This solution of the ester was then reacted with 124.5 gms., mole, of dibutyltin oxide. An exothermic reaction ensued in which the temperature rose from 22 C. to 315 C. 7.8 cc. of water was removed in two hours of refluxing. This toluene solution was filtered by gravity. The toluene was stripped from the batch at 25 mm. pressure to a pot temperature of 80 C. The pressure was then reduced to 8 mm. and the pot temperature was raised to 120 C. The residue, dibutyltin S,S' bis (trimethylnonyl mercaptoacetate), was a cloudy yellow viscous liquid, analysis of which was 12.5% Sn and 7.7% S. Various diluent impurities are present in the product due to the commercial nature of the reactants.

Example VII Diethylene glycol laurate mercaptoacetate was prepared from commercial diethylene glycol monolaurate. An estimated 1 mole of this latter material, 288 gms., was reacted with 95 gms. of mercaptoacetic acid (97%) in'the presence of 50 ml. of toluene. The reaction was completed in 5 hours. This toluene solution was further reacted by adding 124.5 gms. 'of dibutyltin oxide to it. There was an exothermic reaction in which the temperature rose from 23 C. to 29 C. The reaction was completed in about 2 hours wherein 7 cc. of water were removed. The toluene solution was filtered hot by gravity. The clear solution was then stripped to a final pot temperature of 100 C. atlO mm. pressure. The resulting product, dibutyl'tin S,S

Y 6 bis (diethylene glycol laurate mercaptoacetate) analyzed 9.4% Sn and 5.6% S.

Example VI II Ethylene glycol ricinoleate mercaptoacetate was prepared in a manner similar to that used in Example VII. Since the ethylene glycol ricinoleate was a commercial product, the resulting materials were not of a very high purity. The esterso prepared was reacted by adding it to the toluene suspension of the dibutyltin oxide, A. mole, 62.5 gms. An exothermic reaction resulted in which the temperature rose from 23 C. to about 30 C. The theoretical water was removed in about one hour. The solution was filtered and the toluene was stripped. The resulting material was a thick tan liquid in which considerable precipitation resulted. The material analyzed 5.8% Sn and 3.8% S.

Example IX Dibutyl thiomalate was prepared by reacting gms. of thiomalic acid, with an excess of normal butyl alcohol. 1 gm. of para toluenesulphonic acid was removed by washing with a 3% solution of sodium bicarbonate and then with water. After drying, the butyl alcohol was stripped from the dibutyl thiomalate. The ester analyzed 5.7% S. 12.45 gms. of dibutyltin oxide were added to 55.9 gms. of dibutyl thiomalate in 70 cc. of toluene. There was a very slight exothermic reaction. The water of reaction was removed and toluene was vacuum stripped. The residue (dibutyltin S,S' bis (dibutyl thiomalate) was a viscous amber liquid which analyzed 8.8% Sn, 4.7% S.

Example X 2-butyloetanol- 1, 176 gms, and beta mercaptopropionic acid, 100 gms, and 100 cc. of toluene were placed in a reaction flask and refluxed until 16 cc. of water were removed. This esteriflcation proceeded at a somewhat slower rate than the mercapto-acetic acid esterification. The toluene was stripped from this ester. The ester analyzed 10.6% S. The ester, 150 gms., was dissolved in 200 cc. of toluene. 62.5 gms. of dibutyltin oxide were added to the toluene solution and the temperature rose from 19 to 24 C. Toluene was refluxed to remove water and 4.5 cc. were taken off in 3 hours. The toluene solution was filtered. The toluene was stripped from the solution at a pressure of 9 mm. to a pot temperature of The dibutyltin S,S bis (Z-butyloctyl beta meroaptopropionate) was a viscous slightly yellow liquid. It analyzed 14.2% Sn, 7.5% S. Calculated analyses, 14.0% Sn, 8.3% S.

Example XI fluxed until 2 ml. of water were removed. The

toluene solution was filtered. The toluene was 9.3 gms, and 50 ml. of toluene.

I stripped to a pot temperature of 130 C. at 21/; mm. A yellow liquid was obtained weighing 87.1 gms. The dilauryltin S,S' bis (butyl 'mercaptoacetate) analyzed 15.2% Sn, 8.7% S. Calculated analyses 15.8% Sn, 8.5% S.

Example XII Mixed decyl mercaptoacetate was prepared by reacting 1215 gms. of mercaptoacetic acid with 2000 gms. of mixed decanols (product of Carbide and Carbon Chemicals Corp.) in the presence of 12 gms. of para toluene-sulphonic acid. In four hours 240 mls. of water were removed. The toluene was stripped in vacuo and the mixed decyl mercaptoacetates distilled at about 130 C. at mm. pressure. The decyl mercaptoacetate, 62.5 gms, 81.3 grns. tributyltin monochloride, and 160 ml. of toluene were charged into a flask. To this flask was added gradually sodium carbonate, 26.5 ems" 100% in excess of the amount required. On adding the sodium carbonate, the temperature rose from 22 C. to 28 C. After addition, the mixture had a pink coloration. Heat was then applied. The reaction was completed in six hours as evidenced by the removal of water and carbon dioxide from the reaction. The salt residue was filtered and this material was stripped of toluene via vacuum distillation to a pot temperature of 125 C. at 2 mm. pressure. The product was a yellow colored liquid which weighed 107 grams. The tributyltin S decyl mercaptoacetate analyzed 21.3 Sn, 6.7% S. Theoretical analysis for such a material is 22.8% Sn, 6.2% S.

Example XIII Decyl mercaptoacetate, 132 gms, was admixed with dimethyltin oxide, 44 gms., and 150 ml. of toluene. On heating to a temperature of 124 C. 4.9 ml. of water were removed via a Barrett moisture trap. The resulting solution was slight- 1y opaque and white. This solution was filtered by gravity to remove a small amount of solid residue. The clear filtrate was stripped of toluene by vacuum distillation to a pot temperature of 127 C. at 2 mm. pressure. The pot residue which was dimethyltin S, S bis (decyl mercaptoacetate) analyzed 17.98% Sn, 9.7% S. The theoretical analysis for this material was 19.4% Sn, 10.4% S.

Example XIV Decyl mercaptoacetate, 35.8 gms. of a 93% purity, was admixed with butyl stannoic acid, The mixture was heated with stirring and water was removed as it was formed. The reaction was completed in hours. The solution was filtered by gravity and the toluene was stripped in vacuo to a pot temperature of 140 C. at 2 mm. The product was a light yellow liquid weighing 36.7 gms. The product analyzed 13.25% Sn, 11.1% S. The theoretical analysis for this product which is butyltin S.S, S tris (decyl mercaptoacetate) is 137% Sn, 11.0% S.

Example XV Decyl mercaptoacetate, 14.7 gms. of a 93% purity, was admixed with triphenyltin chloride, 22.7 gms, and 55 ml. of toluene. To this mixture was added slowly sodium carbonate, 10.6 gms. The addition of the carbonate and removal of Water of reaction were completed in 3 hours. The material was then filtered by gravity and the toluene was stripped in vacuo to a pot temperature of 130 C. at 2 mm. pressure. The product was a light colored viscous liquid. It analyzed 19.4% Sn, 6.1% S. The theoretical analysis for this triphenyltin S decyl mercaptoacetate is 20.5% Sn, 5.5% S.

Example XVI The methyl ester of thiosalicylic acid was prepared by passing anhydrous hydrogen chloride through a boiling methyl alcohol solution of the technical acid. The ester was separated by addition of dilute acid; washed free of acid; dried and vacuum distilled. Two moles of methyl thiosalicylate, were added to a toluene cc.) slurry of 1 mole of dibutyltin oxide. The oxide dissolved on heating; Water was removed via a moisture trap. The solution was filtered, and then stripped in vacuo. The product, dibutyltin S,S bis (methyl thiosalicylate) analyzed 26.1% Sn, 14.7% S.

Example XVII Thiomalic acid (37.0 gms.- -0.50 moles) was dissolved in methyl alcohol (300 ml.). The solution was stirred while dibutyltin oxide (62.5 gms.- 0.25 moles) was added. The oxide dissolved. The reaction was completed by distilling off the methyl alcohol and water of reaction in vacuo at a pot temperature of C. and then placing the reaction product on a steam bath in an evaporating dish. The product, dibutyltin S, S bis (thiomalic acid) was a grey, low-melting solid which analyzed 18.9% Sn, 11.3% S.

Emample XVIII Mercaptoacetic acid (97%) (48 gms.0.50 mole) was dissolved in toluene (200 ml.). Dibutyltin oxide (62.5 gms.--0.25 mole) was added to the stirred solution. The oxide dissolved on heating. Water of reaction (10.3 ml.) was removed by refluxing the toluene using a Barrett moisture trap. The toluene was stripped in vacuo to a pot temperature of 137 C. The product, di-

butyltin S, S bis (mercaptoacetic acid) was a white crystalline solid which analyzed 28.3% Sn, 15.0% S.

Example XIX ture rose slightly. Heat was applied very slowly to the beaker. As the batch became hotter the mass tended to liquify; some boiling was noted presumably of water. Eventually the whole became liquid. When allowed to cool slowly, crystallization took place at about C. The mass was remelted and heated to about 180 C. When cooled slowly it was observed that the crystallizing point had risen to 129 6.; some weight had been lost during the heating. The mass was then kept hot, in a semi-melted condition for 25 minutes after which it was observed that the crystallizing point had risen to C. and that the product when cooled to room temperature appeared much less crystalline than it had when first produced. Further weight had been lost.

Example XX Part A.Three moles (325.5 grams) of alpha chloropropionic acid were added dropwise to a solution of sodium sulfliydrate (6 moles, 480 grams of 70% sodium sulfhydrate and 250 ml. of water) saturated with hydrogen sulfide. The mixture was stirred and hydrogen sulfide was passed into the solution during the addition. After the acid had been added the solution was heated to reflux for 3 hours.

The solution was then cooled and an excess of hydrochloric acid was added. The solution was heated for three hours to effect complete reaction. It was then cooled and extracted with ether.

The ether extract was evaporated until free of ether and the residue distilled to recover the mercaptoacid. Yield was 90 grams of a clear liquid.

Part B.Two moles of 3,5,5 trimethylhexanol, the 90 grams of alpha mercaptopropionic acid, 100 ml. of toluene and 2 ml. of 47% boron trifluoride etherate were refluxed until the water of esterification had been removed. To the resulting ester, 0.42 mole (104.5 grams) of dibutyltin oxide was added, the mixture refluxed to effect solution of the oxide and removal of water of reaction. The final mixture was stripped under vacuum to leave as a residue dibutyltin S,S bis(trimethylhexyl a mercaptopropionate).

Example XXI The process of Example XX was repeated using 1 mole of f3 bromobutyric acid in place of the a chlorobutyric acid. The other ingredients were used in equivalent amounts. The resulting prodnot is dibutyltin S,S' bis (trimethylhexyl fl-mercaptobutyrate) Example XXII Example XXIII The process of Example XX Was repeated using one mole of alpha bromovaleric acid in place of alpha chloropropionic acid. Dibutyltin .S,S' bis(trimethylhexyl alpha mercaptovaler-ate) resulted.

. Example XXIV Alpha bromocaproic acid was prepared by the Hell-Vollhardt-Zelinsky bromination of 2 moles of caproic acid.

One mole of the a bromocaproic acid was used in the process of Example XXII to yield ultimately dibutyltin S,S bis(trimethylhexyl a mercaptocaproate) Example XXV Two moles of caprylic acid were .brominated by the Hell-Vollhardt-Zelinsky method to yield a bromocaprylic acid.

One mole of the resulting a bromocaprylic acid was used in the process of Example XXII, with the use of butyl alcohol in place of the 3,5,5, tri- 10 methylhexanol, to yield dibutyltin as his (butyl a mercaptocaprylate) Example XXVI Ethyl a mercapto-a-ethylcaproate was prepared by treating one mole of ethyl a bIOlIlO-aethylcaproate with two moles of sodium sulfhydrate in 200 ml. of butyl alcohol saturated with hydrogen sulfide for 4-8 hours at reflux. The resulting ethyl a mercapto-a-ethylcaproate was treated with its equivalent of dibutyltin oxide in refluxing toluene to yield, after removal of water and solvent, dibutyltin S,S' bis(ethyl a mercapto-a-ethylcaproate) Example XXVII Capric acid (one mole) was treated by refluxing for one hour in thionyl chloride (200 ml.). To the resulting solution was then added 1.05 moles of bromine over a period of 2-3 hours. The mixture was allowed to stand overnight, the excess bromine and thionyl chloride removed by vacuum stripping. The residue was added to Water to efiect hydrolysis of the a bromocapryl chloride. This is a modification of the process of Schwenk and Papa, J. Am. Chem. Soc. '70, 3627 (1948). The alphabromo-capric acid was recovered and treated by the process of Example XX to yield dibutyltin S,S' bis(butyl a mercaptocaprate).

Example XXVIII One mole of pel-argonic acid was treated by the process of Schwenk and Papa (J. Am. Chem. Soc. 70,1;3627 (1948)) to yield ethyl a bromopelargona e.

Using the process of Example XXII the ethyl or. bromopelargonate was converted ultimately to dibutyltin S,S bis(butyl a mercaptopelargonate).

Example XXIX Lauric acid was treated by the process of Example XXVII to yield dibutyltin S,S bis(buty1 a mercaptolaurate).

Example XXX One mole of palmitic acid was brominated by the standard Hell-Vollhardt-Zelinsky method. The a bromopalmitic acid was treated by the method of Example XXII to yield dibutyltin S,S bis (butyl a mercaptopalmitate) Example XXXI Two moles of stearic acid was treated by the method of Example XXVIII to yield dibutyltin S,S' bis butyl a mercaptostearate) Example XXXII Two moles of phenylacetic acid were treated by the method of Example XXVIII to yield ethyl a bromophenylacetate. The ethyl a bromophenylacetate was treated with 2-mo1e equivalents of sodium sulfhydrate in 600 ml. of water to yield ethyl a mercaptophenylacetate. This in turn was treated with dibutyltin oxide in boiling toluene to yield dibutyltin s,s bis(ethyl a mercaptophenylacetate) Example XXXIII One mole of diphenylacetic acid was treated by the process of Example XXXII. The intermediate ethyl a bromodiphenylacetate was a bluish green liquid which slowly became yellowish in color after standing. Dibutyltin S,S bis (ethyl a. mercapto diphnylacetate) was the product obtained.

Example XXXIV news a t r re w s t e t d y th nm s 9 Exam e XX v t l d u y ,3" bis(trimethy1hexyl a mercaptodiethylacetate).

Example XXXV Water (1000 grams), 1,3 dibromopropane (2.50 moles, 502 grams) and phenol (2 moles, 138 grams) were stirred and heated to reflux and a solution of sodium hydroxide (1.9 moles, 76 grams) in,250 ml. of water was added slowly over a period of two hours. The mixture was then refluxed for .8 hours. The lower layer was separated, washed with a solution of sodium hydroxide, then with water, and dried over anhydrous sodium sulfate. It Was then vacuum distilled to yield 3 phenoxypropyl bromide. This is a modification of a process given in J. Am. Chem. Soc. 71, 3163 (1949).

The 3-phenoxypropyl bromide was then added to an. equivalent quantity of sodiomalonic ester in refluxing, absolute alcohol sufficient to keep the sodiomalonic ester in solution. The sodiomalonic ester was prepared by dissolving an equivalent quantity of sodium in absolute ethanol (dried by the use of magnexium methoxide) and adding ethyl malonate to the sodium ethox .ide solution. Both these reactions were carried outv with suitable stirring. After the phenoxypropyl bromide had been added, refluxing and stirring were continued for two to three hours. The solution was filtered, and the filtrate was distilled to remove ethanol and finally vacuum distilled to recover the diethyl B-phenoxypropylmalonate.

, The diethyl 3-phenoxypropylmalonate was restr n ers hydrobromica cid (200: ml. of A870 HBr per mole of ester) in such a way as to remove the ethyl alcohol and ethyl bromide formed. More hydrobromic acid was added as necessary. An exit tube from the top of the reflux condenser under the surface of water in a small contame served tdindicate the rate at which car- ;dioxide was evolved from deca'rboxylation of the substituted malonic acid.

The 5-bromoval'e'ric acid formed in this reaction was separated by dissolving in sodium bicarbonate solution, extracting with ether to remove phenol, acidifying the solution and finally extracting with ether. The ether solution was distilled to remove ether and the residue vacuum distilled to recover 5-bromova1eric acid.

Thiourea (2 mole equivalents) and the 5-bromovalericacid were refluxed with sufiicient water to dissolve the thiourea (about 100 ml./2 moles of thiourea) for 2 to 3 hours. Sodium hydroxide (5 m' les/ rnole of fi-bromovale'ric acid in 300 ml. of water) was then added and the solution refluxed for 20 hours. Acidification, ether extraction, and distillation of the ether extract yielded 5- mercaptovaleric acid.

Repeating the process 1n Part B of Example XX using the 5-mercaptovaleric acid yielded dibutyltin 5,8 bis(trimethylhexyl 5-mercaptova1- erate).

Emmtze XXXVI Theprocess of Example XXXV repeatedwhere the 1,3 dibromopropanewas replaced by 1,4 dibromobutane yielded dibutyltin S,S bis(tri'- methylhexyl fi-mercaptocaproate) Example XXXVH Pentamethylene dibromide used in the process of Example XXXV yielded dibutyltin S,S' bis(tri methylhexyl 7-mercaptohexanoate) Example XXXVIII Hexamethylene dibromide used in the process of Example XXXV (with the substitution of butyl alcohol for 3,5,5 trimethylhexanol) yielded dibutyltin S,S' bis(butyl 8-mercaptocaprylate).

Example XXXI X Decamethylene dibromide used in the process of Example XXXV, with the further substitution of butanol for the trimethylhexanol yielded dibutyltin S,S bis(butyl l2-'mercaptolaurate) It has also been discovered and is a feature of this invention that the novel organo-tin derivatives of mercapto acids and mercapto acid esters will function as excellent stabilizers for halogen containing resin compositions, particularly vinyl halide resin compositions containing plasticizers, and when intimately dispersed therein, will provide plastic compositions of improved resistance to heat deterioration. Excellent films are obtained from the aforesaid plastic compositions which exhibit a high degree of stability. The optimum concentration of the novel organo tin derivatives, useful as a stabilizer is between 0.5 'l.0% based on the weight of the vinyl resin. The resin compositions containing this concentration of stabilizer produce a stable and colorless. plas tic film, which remains clear at elevated temperatures as evidenced by the results of the heat tests in Table I. p v

Polyvinyl chloride resins and copolymer resins were employed in these tests. The stabilizer was incorporated into a mixture of parts by weight of resin and 35-50 parts by weight of a plasticizer, or a mixture of plasticizers. The weight of the stabilizer was determined by its analysis. Thus enough stabilizer was used to provide the same weight of combined tin as provided by two parts of dibutyl-tin S,S bis (nonyl mercaptoacetate) (0.374- part of tin by weight). This was done in order to have a means of determining the relative merits of the various compounds.

The mixture was then milled for 5 minute-S on a two-roll differential speed mill heated to 320 to 325 F., and remeveu as a sheet. Portions of the sheet were then placed in a single cavity inold (6 by '6 by 40 mils), and Dreheated to 2'75 F. The mom was placed on a Preco press and raised to 320? F. under 10,000 pounds total pressure. When the mold reached 320 F. the pressure was increased to 40,000 pounds and held until the temperature reached 330* F. This procedure required five ti) five and one-half minutes. The mold and press platens were then cooled and the pressed "sheet removed.

Thepres'sed sheet was cut into one inch by six-inch strips and these placed in clips on a "tray so that the strips'w'ould hang vertically. The tray was then placed in a circulating all oven held at 329 Samples were recovered after one hour, two hours, three hours, and four hours of heat aging. Samples were rated visually, the degree or stability or the vinyl res-in film being represented by the "depth of the colorations, wherein C is colorless, VSY is very slight yellowing, SY is slight yellowing, Y is yellowed, OY is orange yellow, 'rbr "is reddish brown, br is brown, and b1 is black.

TABLE I Composition Appearance After Heat Aging Stabilizer 100 parts resin Plasticizer 1 hr. 2 hr. 3 hr. 4 hr.

none Geon 101 50 parts Flexol DOP dibutyl tin dilaurate. 2 pats/190 parts Geon 50 parts Flexol DOP resin. from Ex. 1 Geon 101 EP (from B. 50 parts Flexol DOP Goodrich 00.; (Dioctylphchalate). polyvinyl chloride resin, homopolymer) same same same e eon s a e grey sta e e Geon EP. Ot l )i VSbXI. (gr y) eon sa e grey sta e gre Geon 101 EP. VSY. y) same from Ex. Ultron 300 (Monsanto Chemical 00., polyvinyl chloride resin). from Ex. 12 same from EX. 13 from Ex. 14 same 2 parts dibutyl tin S,S 40 parts Flexol DOP; bis (nonyl rnercapto- 1Q parts 8-140 (cresyl tat diphenyl phosphate- Monsanto). Do same 30 pa r %sDOP;parts C O VSY SY. Do same 20525 DOP;parts C O VSY SY. Do same IO p ESDOPMO parts 0 O SY Y. D Geon 101 EP (polyparts DOP;10ports O 0 O 0.

vinyl chloride resin, Lmdol (trioresyl homopolymer). Phosphate, Oelanese Corp. of Am.) Do same 30p artsDOP;20parts O 0 O VSY.

111 Do same 20 p rc1is DOP;30parts O O VSY VSY;

m o Do same 10Ip 1rs DOP;40parts O G VSY VSY.

111 0. Do Geon 101 EP (poly- 40parts DOP;10parts O O 0. 0.

vinyl chloride resin, an aryl allryl phoshomopolymer). phate plastlcizer. D same 30 parts DOP; 20 parts O O-.. C- VSY.

an aryl alkyl phosphate plastioizer. Do same 20 parts DOP; 30 parts 0. O.-. C. VSY.

an aryl alkyl phosphate plasticizer. 7 D0 same l0partsDOPz40parts C C VSY. SY,

an aryl alkly phosphate plasticizer. 2.2 parts dibutyl tin, Geon 202 (polyvinyl 401181128 DOP C C C 0.

8,8 bis(nony1 merchloride-polyvinylcapto-acetate) ldene chloride copolymer resln. F. Goodrich Go). Do VR-IO (Naugatuck 35partsDOP C O O 0.

Chem. 00.). Do Pliovic A (polyvinyl 35parts DOP VSY VSY SY Y,

chloride resin, Goodyeag Tire & Rubber 0. D U-30n 35parts DOP;15parts O O VSY,

of an aryl alkyl phosphate plasticizer. Geon 101 parts DOP light grey light grey light grey, U-300. m O O, QYNA (polyvinyl same O VSY chloride-polyvinyl acetate copolymer, Bakelite). 2 parts dibutyl tin Geon 101 20 parts DOP; 20 parts Y OY dilaurate. of an aryl alkyl phosphate plasticizer. Do do 37.5 parts DOP; Y OY. rbr

parts of an aryl alkyl phosphate plasticizer. 2 parts dibutyl tin U VSY I'bl maleate. 2 parts dibutyl tin do 20 Iports DOP; 20 parts OY rbr dilauratei mdol.

This table clearly discloses the unusual stabilizing activity of the novel mercapto-acid ester derivatives of organo tin compounds in comparison to a resin Without a stabilizer and with known stabilizers. A colorless film evidences the highest degree of stability. This superior stabilizing efiect is particularly evident in polyvinyl chloride resin compositions containing phosphate-type plasticizers, the use of Which has heretofore been limited due to their instability. The novel organo-tin compounds of the present invention impart sufficient stabilization to such compositions to permit making stable fireproof plastic articles therefrom.

In order to test the efiectiveness of the compounds of this invention as light stabilizers, films of '5 mil thickness were prepared by the same methods described above. In each case dibutyltin S,S'bis( nonyl mercaptoacetate) was used as a stabilizer. These films were exposed in an Atlas Electric Devices Company Fadeometer FDA-2 and examined daily until failure occurred. The compositions of the films, the time at winch failure was first noted and the type of failure are given in Table II. Type of failure is indicated by a code in which A represents sweating, B specking or spotting, S stifiening and E embrittlement. It should be noted that up to 1000 hours no stiffening or embrittlement had occurred.

TABLE II Film composition Fading, Type of hours failure Resin Plasticizer 100 parts polyvinyl 40 arts of dioctyl phthalate 500l000 A chloride resin DOP); 10 parts ofan aryl (Geon 101 El). alkyl phosphate (of an aryl alkyl phosphate).

Do 30 parts DOP; parts of an 2 aryl alkyl phosphate. 1 000 AB Do 20 parts DOP; parts oi an aryl alkyl phosphate. 1 Y

440 A Do 10 parts DOP; 40 parts of an aryl'alkyl phosphate. 1 10) parts polyvinyl parts DOP; 15 parts of an chloride resin (U- aryl alkyl phosphate' 1 Q 300). part dibutyltinv S,S bis- 1 000 AB (nonyl mercaptoacetate).

Do 25 parts DOP; 25 parts of an 500 A aryl alkyl phosphate; 1 700 AB part dibutyl tin 8,8 bis- 1 000 AB (nonyl mercaptoacetate).

Do 15 parts DOP; 35 parts of an 520 A aryl alkyl phosphate; l 700 AB part dibutyl tin S,S bis- 1 000 AB (nonyl mercaptoacetate).

Other uses of the organo-tin-mercaptoacid and mercapto acid ester derivatives are as stabilizers for other chlorinated materials, as rubber accelerators, rubber antioxidants, lube oil additives and polymerization accelerators.

While the invention has been described with reference to various examples and embodiments, it will be apparent to those skilled in the art that various modifications may be made, and equivalents substituted therefor, without departing from the principles and true nature of the present invention.

Having described the invention, what is desired to be secured by Letters Patent is:

1. A compound having the formula wherein n is an integer from 1 to 3, R is selected from the group consisting of alkyl, aryl and aralkyl radicals, R" is from the group consist ing of hydrogen, alkyl, aryl, and aralkyl radicals, and R is an alkylene radical.

2. A heat and light stable resin composition comprising a polymeric vinyl resin containing vinyl halide units and about /2 to about 10% by weight of a compound as defined in claim 1.

3. A heat and light stable resin composition comprising a halogen containing resin, a plasticizer, and a compound as defined in claim 1 as a stabilizing agent intimately dispersed there- 4. A heat and light stable resin composition comprising a halogen containing resin, 2. phosphate plasticizer, and a compound as defined in claim 1 as a stabilizing agent intimately dispersed therein.

5. Dibutyltin 8,8 acetate).

6. Dimethyltin 5,8 bisdecyl mercapto acetate) '7. Dibutyltin S,S' bis(mercapto acetic acid).

8. A composition comprising a halogen-containing resin stabilized with a compound of the character defined in claim 5.

9. A composition comprising a halogen-containing resin stabilized with a compound of the character defined in claim 6.

10. A composition comprising a halogen-containing resin stabilized with a compound of the character defined in claim '7.

11. As a composition of matter, a hydrocarbon tin derivative of an aliphatic monocarboxylic mercapto-acid, containing the group 12. A composition of matter as described in claim 11, wherein the aliphatic monocarboxylic mercapto-acid is an alkyl mercapto-acid.

13. A composition of matter as described in claim 18, wherein the aliphatic monocarboxylic mercapto-acid ester is an alkyl ester of an alkyl mercapto-acid.

14. A heat and light stable resin composition comprising a polymeric vinyl resin containing vinyl halide units and a compound as defined in claim 11 in stabilizing amounts.

15. A heat and light stable resin composition comprising a halogen containing resin, a plasticizer, and a compound as defined in claim 11 as a stabilizing agent intimately dispersed there- 1n.

16. A heat and light stable resin composition comprising a halogen containing resin, a phosphate plasticizer, and a compound as defined in claim 11 as a stabilizing agent intimately dispersed therein.

17. A method of preparing compounds as defined in claim 1 which comprises reactin a hydrocarbon substituted compound of the class consisting of oxides, hydroxides and halides of tin,

bis(n-octadecyl mercapto and stannoic acids with a compound having a formula HSR'COOR in which t is selected from the group consisting of hydrogen, alkyl, aryl and aralkyl radicals, and R is an alkylene radical- 18. As a composition of matter, a hydrocarbon tin derivative of an aliphatic monocarboxylic mercapto-acid ester containing the group 19. Aheat and light stable resin composition comprising a polymeric vinyl resin containing 17 vinyl halide units and a compound as defined in claim 18 in stabilizing amounts.

20. A heat and light stable resin composition comprising a halogen containing resin, a plasticizer, and a compound as defined in claim 18 as a stabilizing agent intimately dispersed therein.

21. A heat and light stable resin composition comprising a halogen containing resin, a phosphate plasticizer, and a compound as defined in 18 claim 18 as a stabilizing agent intimately dispersed therein.

22. Dibutyltin S,S' mercaptoacetate) 23. A composition comprising a halogen-containing resin stabilized with a compound of tin character defined in claim 22.

ELLIOTT L. WEINBERG. ERNEST W. JOHNSON.

N 0 references cited.

bis(3,5,5 trimethylhexyl 

1. A COMPOUND HAVING THE FORMULA 